Preheat oven to 350 degrees F. Butter a 9-inch springform pan or pie pan. Set aside.
Whisk together flour, baking powder, and salt in a medium bowl. Set aside.
In the bowl of a stand mixer, beat the butter and sugar until pale and fluffy, about 3 minutes. Add in egg, coconut milk, vanilla, and coconut extract. Mix until combined.
Gradually mix in the dry ingredients. Stir in the coconut. Transfer batter to prepared pan. Arrange raspberries on top of batter and slightly press them down.
To make the coconut streusel topping, in a small bowl combine flour, brown sugar, and coconut. Add in butter pieces and mix together with your fingers until crumbly. Top the cake with coconut streusel.
Bake cake for 45-50 minutes or until it is golden brown and firm to the touch. Let cool in pan for 15 minutes. Remove from pan and cool completely on a wire cooling rack. Cut into slices and server.
Note-the cake will keep up to 2 days, stored in an air-tight container on the counter.